test: check noAssert option in buf.write*()

Add test to cover previously untested `noAssert` functionality in
buf.write*() functions.

PR-URL: nodejs#10790
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/parallel/test-buffer-write-noassert.js

@@ -0,0 +1,48 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+
+// testing buffer write functions
+
+function write(funx, args, result, res) {
+  {
+    const buf = Buffer.alloc(9);
+    assert.strictEqual(buf[funx](...args), result);
+    assert.deepStrictEqual(buf, res);
+  }
+
+  {
+    const invalidArgs = Array.from(args);
+    invalidArgs[1] = -1;
+    assert.throws(
+      () => Buffer.alloc(9)[funx](...invalidArgs),
+      /^RangeError: (?:Index )?out of range(?: index)?$/
+    );
+  }
+
+  {
+    const buf2 = Buffer.alloc(9);
+    assert.strictEqual(buf2[funx](...args, true), result);
+    assert.deepStrictEqual(buf2, res);
+  }
+
+}
+
+write('writeInt8', [1, 0], 1, Buffer.from([1, 0, 0, 0, 0, 0, 0, 0, 0]));
+write('writeIntBE', [1, 1, 4], 5, Buffer.from([0, 0, 0, 0, 1, 0, 0, 0, 0]));
+write('writeIntLE', [1, 1, 4], 5, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeInt16LE', [1, 1], 3, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeInt16BE', [1, 1], 3, Buffer.from([0, 0, 1, 0, 0, 0, 0, 0, 0]));
+write('writeInt32LE', [1, 1], 5, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeInt32BE', [1, 1], 5, Buffer.from([0, 0, 0, 0, 1, 0, 0, 0, 0]));
+write('writeUInt8', [1, 0], 1, Buffer.from([1, 0, 0, 0, 0, 0, 0, 0, 0]));
+write('writeUIntLE', [1, 1, 4], 5, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeUIntBE', [1, 1, 4], 5, Buffer.from([0, 0, 0, 0, 1, 0, 0, 0, 0]));
+write('writeUInt16LE', [1, 1], 3, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeUInt16BE', [1, 1], 3, Buffer.from([0, 0, 1, 0, 0, 0, 0, 0, 0]));
+write('writeUInt32LE', [1, 1], 5, Buffer.from([0, 1, 0, 0, 0, 0, 0, 0, 0]));
+write('writeUInt32BE', [1, 1], 5, Buffer.from([0, 0, 0, 0, 1, 0, 0, 0, 0]));
+write('writeDoubleBE', [1, 1], 9, Buffer.from([0, 63, 240, 0, 0, 0, 0, 0, 0]));
+write('writeDoubleLE', [1, 1], 9, Buffer.from([0, 0, 0, 0, 0, 0, 0, 240, 63]));
+write('writeFloatBE', [1, 1], 5, Buffer.from([0, 63, 128, 0, 0, 0, 0, 0, 0]));
+write('writeFloatLE', [1, 1], 5, Buffer.from([0, 0, 0, 128, 63, 0, 0, 0, 0]));